Transformer circuits



March 31, 1964 E. HONORE ETAL 3,127,555

TRANSFORMER cIRcu ITs Filed Jan. 16, 1958 4 Sheets-Sheet 1 FIG-5 Ha 2a Fl6-6 i;

March 31, 1964 E. HONORE ETAL 3,127,555

TRANSFORMER CIRCUITS Filed Jan. 16, 1958 4 Sheets-Sheet 2 FIG.4

March 31, 1964 HQNORE ETAL 3,127,555

TRANSFORMER CIRCUITS Filed Jan. 16, 1958 4 Sheets-Sheet s E 31 7 if N 3 J7 FIG-8 March 31, 1964 E. HONORE ETAL TRANSFORMER CIRCUITS 4 Sheets-Sheet 4 Filed Jan. 16, 1958 FIGJC FIG."

United States Patent ()flice 3,127,555 Patented Mar. 31, 1964 3,127,555 TRANSFORMER CIRCUITS Etienne Honorand Emile Torcheux, Paris, France, assignors to Compagnie Gencrale de Telegraphic Sans Fil, a corporation of France, and Societe Marocaine de Recherches dEtudes et de Developpements Somarede, a corporation of Morocco Filed Jan. 16, 1958, Ser. No. 709,383 Claims priority, application France Jan. 18, 1957 4 Claims. (Cl. 323-75) The present invention relates primarily, although not exclusively, to analog computer circuits of the type described in our United State Patent No. 2,785,853 of March 19, 1957.

This patent discloses analog computer circuits comprising at least one pair of quadripoles. Each quadripole has two input and two output terminals. The output terminals of one quadripole are respectively connected to the input terminals of another quadripole and each quadripole forms a resonant circuit if its input or output ter minals are shorted. All the quadripoles are, in addition, connected in parallel with respect to two common terminals and the whole circuit is resonant if all its external terminals which are not connected together are shorted. As described in the U8. Patent 2,785,853, such circuits are particularly adapted for performing elementary arithmetical operations on voltages which may be representative of any kind of magnitudes.

In the various embodiments, shown in the above mentioned patent, the quadripoies used in the disclosed circuits comprise variable capacitors whose value is varied in order to vary the respective coeflicients with which the applied voltages are affected. However, under certain conditions, it may be more convenient to vary the inductances incorporated into the quadripoles and it is an object of the present invention to provide such quadripoles which may be used for building analog computer circuits of the above type, alone or in combination with quadripoles such as those described in the US. Patent 2,785,853. The invention is not limited to analog computer circuits described in this patent, but is more generally concerned with all the circuits in which the quadripole of the invention can be used.

More particularly, the invention provides a variable inductance device particularly suitable for use in the above circuits.

The invention will be better understood from the following description taken in conjunction with the appended drawing, wherein:

FIG. 1 illustrates a quadripole according to the invention;

FIG. 2 schematically shows an embodiment of the variable induction device according to the invention;

FIG. 3 shows an embodiment of the variable induction assembly according to the invention for use in the quadripole of FIG. 1;

FIG. 4 shows a variation of the same assembly;

FIGS. 5 and 6 illustrate tripoles according to the invention;

FIG. 7 shows a variable inductance device according to the invention for use in the tripoles of FIGS. 5 and 6.

FIG. 8 shows a preferred embodiment of the device of FIG. 4;

FIG. 9 shows very diagrammatically a variation of a quadripole comprising devices of FIG. 8;

FIG. 10 illustrates an elementary computing circuit comprising a quadripole as shown in FIG. 1; and

FIG. 11 shows a particular application of the quadripole according to the invention.

The same references are used'throughout the specification to designate the same elements.

The quadripole illustrated in FIG. 1 operates on a predetermined frequency. It comprises two input terminals and 11b and two output terminals 12a and 12b. A fixed capacitor 13 is connected across input terminals 11a and 11b and a similar capacitor 14 is connected across output terminals 12a and 12b. The respective susceptance of these capacitors is K.

Terminals 11a and 11b are connected to output terminals 12a and 112% through respective variable inductances 15, the susceptance of which is -(K+X) and to terminals 12b and 12a through respective inductances in, the susceptance of which is -(KX). The term K has a fixed value and the term X may vary between K and +K, while maintaining the same value in the four inductances of the quadripole. In other words, the respective susceptances of each coil 15 or 16 vary from 0 to 2K.

It will be appreciated, under these conditions, that if in a quadripole one of the capacitors 13 and 14 is short circuited, the remaining circuit is tuned to frequency i Such quadripoles present the same features as those disclosed in the above mentioned US. Patent 2,785,853. In particular, at least two quadripoles may be combined, as disclosed in this patent and as briefly recalled at the outset of the present specification, to form a computer circuit. If voltages of frequency i are applied to a plurality of free terminals of such circuit, voltages of the same frequency will appear across the remaining free terminals, these voltages being related by the expression: I/1X1+V2X2+ V 0, wherein X1 X are the respective values of X in the quadripoles forming the circuit and V V the respective voltages appearing across, or as the case may be fed to, the terminals of the circuit.

It may be shown, in the same way as in the above patent that any error, due to the fact that the impedances applied to the terminals of the network are not infinite, intervene in the second order only.

FIG. 2 shows an embodiment of a variable inductance device provided by the invention and particularly suitable for use in the quadripole according to the invention.

This device comprises a conventional high frequency coil pct 11%, wherein coil W1 is located. Opposite the free face of the winding, is placed a plane metal plate 102, which is movable perpendicularly to its plane and along the core axis. The induction flux of winding 101 closes through plate 102. Any change in the position of this plate will cause a variation of the air-gap and consequently, of the reluctance of the magnetic circuit and thus of the impedance of coil 101.

Neglecting the reluctance of the metal portion of the magnetic circuit, which may be done with good approximation, the susceptance of the inductance coil will have substantially the value: S: -Ne, where e is the air gap, and N a constant, independent of e.

FIG. 3 shows a first example of an arrangement of inductance coils adapted for use in the quadripole of FIG. 1.

A first pair of windings 15 and 16 are respectively placed in pots 104 and 104', similar to pot 103 in FIG. 2. A plate 21 is placed between pots 104 and 104. The respective induction fluxes of both windings 15 and 16 closing therethrough. The second pair of windings 15 and 16 forms a similar assembly as in FIG. 3. A system of rods 1W5 enables plates 21 to be moved simultaneously in such a manner that air gaps 10421, 10421 remain respectively equal in the two assemblies.

Calling 2c the distance separating the free faces of windings 15 and 16, when the two air gaps 104-21 and Mid -21 are equal toe the common value of the susceptance of inductance coils 15 and 16 is Ne If in end covers 52.

plate 21 moves a distance d in the direction of one of the pots, for example pot 104, the susceptance of coil 15 becomes: N(e +d) and that of coil 16: N(e -d).

The two susceptances are thus of the same value as those usedin the quadripole of FIG. 1. This is clearly apparent, if the above two terms are written -(K+X) and -(KX), with K:Ne and X=Nd.

The coil terminals are respectively connected to input terminals 11a and 11b of the quadripole and to its output terminals 12a and 12b, as shown in FIG. 1.

In the embodiment of FIG. 4, the two windings 15 and the two windings 16 are respectively wound in a single pot, 104 or 104'. The operation of this assembly is obviously similar to that in FIG. 3.

FIGS. 5 and 6 represent tripoles or quadripoles with one input and one output terminal grounded and which can be used in lieu of the quadripole of FIG. 1, provided the basic condition that the circuit is resonant with the input or the output terminals shorted is fulfilled.

In'FIG. 5 input terminal 11b and output terminal 12b are grounded.

A fixed capacitor 13a is connected between terminal 11a and ground and a capacitor 14a of the same susceptance 2K is connected between the terminal 12a and 'grou'nd.

Coils 15 and 16 are connected in the same manner and have the same value as in FIG. 1.

It will be appreciated that if either of the two capacitors is short-circuited by grounding terminal 11a or terminal 12a, the remaining circuit becomes resonant,

whatever the value of X, and therefore can be used in the same way as quadripoles in the above mentioned computer circuits.

FIG. 6 is an alternative embodiment of the tripole of FIG. 5. It comprises the same elements as those of FIG. 5, except that a capacitor 19 is connected across terminals 11a and 12a, and that the susceptance of capacitors 13b, 14b and 19 is K.

FIG. 7 shows how the arrangement of FIG. 3 can be i applied to the quadripoles in FIGS. 5 and 6. As may be seen from FIG. 7, one of the pots of the right hand assembly has been eliminated since there is only one coil in FIGS. 5 and 6. For the remainder, FIG. 3 and FIG. 7 are entirely similar.

FIG. 8 shows a preferred embodiment of the variable inductance device of FIG. 2 and more precisely of the variation of this device shown in FIG. 4.

As may be readily seen, in this latter device only a small portion'of the air gap is actually used for varying the magnetic flux, i.e. the inductance of the two coils 15 or 16. Further, it can be observed that, when "plate 21 is moved, for example from pot 104 towards pot 104', magnetic losses, due to the flux dispersion, tend to increase between magnetic pieces 104 and 21 and tend to decrease between magnetic pieces 104' and 21. Finally the two magnetic circuits closing themselves through plate 21 are not decoupled. These last two facts involve that the respective susceptances of the coils do not vary linearly with the corresponding air gaps.

All these drawbacks are avoided in the device shown in FIG. 8. This device comprises an envelope 5t) made of a non magnetic material. Theenvelope comprises a cylinder 51 and two end covers 52. A shaft 53, also made of a non magnetic material, is positioned within the envelope for axial movement therein. his provided at both ends with journals 54, which are supported with sumcient clearance in bearings 55, provided In the envelope 50 are mounted two symmetrical magnetic assemblies 56 and 57, corresponding to pots 104 and 104' of FIG. 4 respectively. Each assembly comprises a fixed magnetic piece 58, having a central hub 59, and a fixed magnetic ring 60, spaced apart from hub 59.

In the respective openings 6110f the two rings 60 are located armatures 63 and 64 which are fixed on shaft 53 and movable therewith, providing variable width air gaps 69 in cooperation with hubs 59. Elements 63 and 64 are spaced by an air gap and are integrally connected by a non magnetic joint 65. Windings 67, corresponding to windings 15 of FIG. 4, are located in the space limited by fixed magnetic pieces 58 and 60 and the movable armature 63. This space is closed by a magnetic ring 69. Similar windings 66 are provided in the same way in assembly 57.

It may be readily seen that an air gap 69, the width of which varies as shaft 53 moves to and fro, i.e. towards hub 59 and away from hub 59, is entirely within the coil and the entire extent thereof is traversed by the magnetic flux. The dispersion flux is small and is, in addition, substantially constant, whatever the position of the armatures 63 and 64. It should also be noted that the respective magnetic fluxes of the two assemblies 56 and 57 are thoroughly separated by non magnetic pieces or by air gaps.

As diagrammatically shown in FIG. 9, the action of the constant dispersion flux can be balanced by small capacitors 17 and 18, inserted in series with the corresponding induction coils 15 and 16.

Of course the quadripoles of the type disclosed in the present application may be combined with quadripoles such as those described in the above mentioned Patent No. 2,785,853. Such a circuit is shown in FIG. 10. It comprises the quadripole 1 of FIG. 1 and a quadripole 2 of the type used in the above patent, i.e. having two fixed capacitors 35 and two fixed coils 34.

It is readily seen that, in this case, the output capacitor 14 of quadripole 1 and the input inductance 34 of quadripole 2 may form an antiresonant circuit, tuned to frequency f,,, and may thus be eliminated. Therefore they are shown in dotted lines.

FIG. 11 shows a very interesting use of the quadripole according to the invention, more particularly in the low frequency range.

A source 20 of constant voltage and of a frequency of, for example, 400 c./s., is connected between input terminals 11a and 11b. Between output terminals 12a and 12b is connected a load 21 the value of which is R. It may be shown that the power P absorbed by the latter is:

P=K.R.X .V where K and X have the same value as above.

This device thus enables the power absorbed in the load 21 to be varied simply by varying the value of X.

This device offers the following advantages:

(a) Pots of small size, for example a few square centimeters in cross-section, enable a comparatively high power to be controlled, for example a power of the order of the kilowatt, for a displacement of the movable armature of the orderof a millimeter;

(b) The power dissipated in the pot and in the windings is extremely low. It is of the order of magnitude of the maximum controlled power, divided by the Q factor of the coils, i.e. of the order of a few watts;

(c) The magnetic forces acting on the movable armature are, to a first approximation, balanced in all positions;

(d) The source of energy sees always the assembly as a pure resistance.

Of course capacitors 13 and 14 of the quadripoles and tripoles according to the invention, may be substituted by tuned dipoles, as explained in our application Improvements in Analog Computer Circuits Serial No. 709,391, now abandoned, filed the same date as the present application.

What we claim is:

1. A quadripole for computer and transformer circuits, said quadripole comprising a pair of input and output terminals, connecting means for applying an alternating electrical magnitude having a predetermined frequency between said input terminals, first and second capacitors of equal value connected across said input and output terminals respectively, a first pair of variable inductance coils for connecting one input terminal to each output terminal, a second pair of variable inductance coils for connecting the other input terminal to each output terminal, means for varying the inductance of said coils, the sum of the susceptances of said coils remaining constant and being at said predetermined frequency equal to K, K having a fixed value, said quadripole also including two pairs of coaxial hollow ringshaped induction pots, each of the pots having two polar surfaces, a shaft extending and movable along the common axis of the pots and carrying two magnetic armatures respectively associated with said pots, said armatures being magnetically insulated from each other and each having two polar surfaces respectively facing the polar surfaces of the respective pots and separated therefrom by respective gaps, one of said gaps between each armature and the respective pot being variable and extending normally to said common axis, the pots of each pair respectively receiving one coil of one of said pairs of coils and one coil of said other pair of coils, said respective magnetic armatures being movable between the respective associated pots for increasing the gap between itself and one of the pots while simultaneously decreasing the gap between itself and the other pot.

2. A quadripole according to claim 1 further comprising capacitors respectively connected in series with said coils for balancing the respective constant dispersion fluxes thereof.

3. A circuit according to claim 2 comprising means for grounding one of said input and one of said output terminals, said quadripole forming a resonant circuit with one of said pairs of terminal shorted.

4. A circuit according to claim 3 comprising a further capacitor connecting one of said input terminals to one of said output terminals, said further capacitor and said capacitors having the same value.

References Cited in the file of this patent UNITED STATES PATENTS 1,918,393 Holden July 18, 1933 2,395,515 Stoller Feb. 26, 1946 2,581,359 Clark Jan. 8, 1952 2,643,869 Clark June 30, 1953 2,679,628 Matthews May 25, 1954 2,758,288 Shannon et al Aug. 7, 1956 2,785,853 Honor et al Mar. 19, 1957 2,873,431 Marsh Feb. 10, 1959 

1. A QUADRIPOLE FOR COMPUTER AND TRANSFORMER CIRCUITS, SAID QUADRIPOLE COMPRISING A PAIR OF INPUT AND OUTPUT TERMINALS, CONNECTING MEANS FOR APPLYING AN ALTERNATING ELECTRICAL MAGNITUDE HAVING A PREDETERMINED FREQUENCY BETWEEN SAID INPUT TERMINALS, FIRST AND SECOND CAPACITORS OF EQUAL VALUE CONNECTED ACROSS SAID INPUT AND OUTPUT TERMINALS RESPECTIVELY, A FIRST PAIR OF VARIABLE INDUCTANCE COILS FOR CONNECTING ONE INPUT TERMINAL TO EACH OUTPUT TERMINAL, A SECOND PAIR OF VARIABLE INDUCTANCE COILS FOR CONNECTING THE OTHER INPUT TERMINAL TO EACH OUTPUT TERMINAL, MEANS FOR VARYING THE INDUCTANCE OF SAID COILS, THE SUM OF THE SUSCEPTANCES OF SAID COILS REMAINING CONSTANT AND BEING AT SAID PREDETERMINED FREQUENCY EQUAL TO -K, K HAVING A FIXED VALUE, SAID QUADRIPOLE ALSO INCLUDING TWO PAIRS OF COAXIAL HOLLOW RINGSHAPED INDUCTION POTS, EACH OF THE POTS HAVING TWO POLAR SURFACES, A SHAFT EXTENDING AND MOVABLE ALONG THE COMMON AXIS OF THE POTS AND CARRYING TWO MAGNETIC ARMATURES RESPECTIVELY ASSOCIATED WITH SAID POTS, SAID ARMATURES BEING MAGNETICALLY INSULATED FROM EACH OTHER AND 